The present invention relates to hot stretch-wrap forming of metal parts and more particularly to the stretch-wrap forming of elongated metal parts such as sheet stock, extrusions and preshaped parts which are normally extremely difficult to stretch-wrap form and when made of titanium, titanium alloys and similar metal require heating of the part to its forming temperature (up to 1,500.degree. F) before satisfactory results can be obtained.
Stretch-wrap forming of flat, hat sections, joggle section, etc. without heating the part to its forming temperature often results only in bending of the part with the stresses on the convexed section of the part often exceeding the elastic limits of the part and the concaved section of the part often being in contraction resulting in a tension failure in the convexed section, a wrinkled concaved section, or both.
In the prior art only flat workpieces have been formed by hot stretch forming and the methods of heating have been limited to heating by heat lamps of imbedding heater units in the forming die. The amount of power required to heat the die and the part combined with the complexity of the heating devices make the prior art methods and devices impractical, particularly for hot stretch-wrap forming of titanium and similar metals.